公开(公告)号：JP2001358694A

公开(公告)日：2001-12-26

申请号：JP2001116607

申请日：2001-04-16

Applicant: LUCENT TECHNOLOGIES INC

Inventor： LAROIA RAJIV ,  LI JUNYI ,  RANGAN SUNDEEP ,  VISWANATH PRAMOD

IPC: H04B1/713 ,  H04B1/7143 ,  H04B1/7156 ,  H04B7/26 ,  H04J11/00 ,  H04L5/02 ,  H04L27/26 ,  H04J13/00

Abstract: PROBLEM TO BE SOLVED: To enable a mobile user device to seedily discriminate and synchronize with a downlink of the base station sending the intensest signal through an orthogonal frequency-division multiplex(OFDM) system, based upon a spread- spectrum multiple access(SSMA) system. SOLUTION: The base station discrimination is actualized by finding the gradient of the most intense received pilot signal (having maximum energy). A pilot tone hopping series is based upon a Latin square series. With the pilot tone hopping series based upon Latin square, the need that the mobile user device has in only for determining the frequency of a pilot tone at a certain time. The gradient and initial frequency shift of the pilot tone hopping series having the highest reception power are determined, by using a natural maximum energy detector. The natural gradient of the pilot hopping series is used to discriminate the base station having the most intense down-link signal.

公开(公告)号：JP2001230753A

公开(公告)日：2001-08-24

申请号：JP2000389810

申请日：2000-12-22

Applicant: LUCENT TECHNOLOGIES INC

Inventor： LAROIA RAJIV ,  LI JUNYI ,  UPPALA SATHYADEV VENKATA ,  RANGAN SUNDEEP

IPC: H04J11/00 ,  H04B1/7136 ,  H04B1/7143 ,  H04L5/02 ,  H04B1/713

Abstract: PROBLEM TO BE SOLVED: To provide radio and other communication systems using an orthogonal frequency division/multiplex system based on especially spread spectrum multiplex access. SOLUTION: In the case of a transmitter, a sequence generator and a sequence allocation device are used for generating and allocating tone sequence to a user on a time slot base by combining them with the tone allocation device of the user. In the case of a receiver, the sequence generator and the sequence allocation device are used for generating sequence and identifying input tone sequence to the user on the time slot base by combining them with the user tone identification device.

公开(公告)号：JP2002124900A

公开(公告)日：2002-04-26

申请号：JP2001235911

申请日：2001-08-03

Applicant: LUCENT TECHNOLOGIES INC

Inventor： LAROIA RAJIV ,  RANGAN SUNDEEP

IPC: H01Q3/26 ,  H04B7/08 ,  H04B7/26 ,  H04L1/06

Abstract: PROBLEM TO BE SOLVED: To provide an adaptive antenna array technique to be used in an orthogonal frequency division multiplex spread spectrum multiple access(OFDM- SSMA) cellular wireless system. SOLUTION: A base station receiver is mounted with an adaptive antenna gain algorithm 126 for estimating a space covariance matrix related with each mobile station. The space covariance matrix in one base station is decided based on the hopping sequence of the mobile stations, and correlation between the signals received from the mobiles stations is provided by different antenna elements 114 in an antenna array. The estimated value of an interference matrix is generated concerning K pieces of mobile stations from the individual space covariance matrixes and the mean space covariance matrix, and array responses related with the respective mobile stations are generated from the estimated value of the interference matrix. Then, antenna weighting is decided from the array response related with the prescribed mobile station, and the antenna weighting is applied to the signal received form the prescribed mobile station.

公开(公告)号：JP2001257657A

公开(公告)日：2001-09-21

申请号：JP2001033049

申请日：2001-02-09

Applicant: LUCENT TECHNOLOGIES INC

Inventor： LAROIA RAJIV ,  LI JUNYI ,  RANGAN SUNDEEP ,  UPPALA SATHYADEV VENKATA

IPC: H04J11/00 ,  H04B7/26 ,  H04J3/06 ,  H04L5/02 ,  H04L7/10 ,  H04L27/26

Abstract: PROBLEM TO BE SOLVED: To provide structuring, detection and estimation technology of a signal used for uplink timing synchronization and access control in a wireless communication system adopting the orthogonal frequency division multiplex system(OFDM) or other types. SOLUTION: In an illustrative embodiment of this invention, a timing and access signal transmitted in designated timing and a designated access interval is structured with an orthogonal multi-tone signal. The multi-tone signal can be obtained similarly to the case with a multi-tone signal used for transmission of OFDM data except for correspondence of the multi-tone signal to a timing error of a mobile station not synchronized yet through the extension of a cyclic prefix related to reception of the signal by a base station.

公开(公告)号：JP2001257641A

公开(公告)日：2001-09-21

申请号：JP2001033039

申请日：2001-02-09

Applicant: LUCENT TECHNOLOGIES INC

Inventor： LAROIA RAJIV ,  LI JUNYI ,  RANGAN SUNDEEP ,  UPPALA SATHYADEV VENKATA

IPC: H04J11/00 ,  H04B7/26 ,  H04L5/02 ,  H04L7/00 ,  H04L27/26

Abstract: PROBLEM TO BE SOLVED: To provide a technology to realize uplink timing synchronization and access control with respect to a wireless communication system in general especially in a multi-access wireless communication system. SOLUTION: A mobile station of this invention transmits a general-purpose uplink access signal at any of intervals. When this access is permitted, a base station transmits access confirmation including initial timing and power correction together with designation of an initial channel at which the mobile station can start call setup process. For re-synchronization, the mobile station transmits a timing synchronizing signal in exclusive timing and at an access interval. The base station measures the arrival time of the signal and returns proper timing correction. Thus, the orthogonality between mobile stations can surely be maintained.

公开(公告)号：AU782983B2

公开(公告)日：2005-09-15

申请号：AU1827901

申请日：2001-02-02

Applicant: LUCENT TECHNOLOGIES INC

Inventor： LAROIA RAJIV ,  LI JUNYI ,  RANGAN SUNDEEP ,  VENKATA SATHYADEV

IPC: H04J11/00 ,  H04B7/26 ,  H04J3/06 ,  H04L5/02 ,  H04L7/10 ,  H04L27/26 ,  H04L7/04 ,  H04B7/208

Abstract: Timing and access signals, to be transmitted in designated timing and access intervals, are constructed from orthogonal multitone signals. The multitone signals may be similar to multitone signals used in OFDM data transmission, except that a cyclic prefix, which is associated with reception of the signals in a base station, is extended to cover the timing errors of mobile stations not yet synchronized. Design techniques which optimize the time resolvability and peak-to-average ratio of the multitone signals, an efficient fast Fourier transform (FFT) based technique for maximum likelihood timing estimation, and a robust linear filtering technique for averaging timing estimates from different synchronizations, are also provided.

公开(公告)号：CA2338471A1

公开(公告)日：2001-10-18

申请号：CA2338471

申请日：2001-02-27

Applicant: LUCENT TECHNOLOGIES INC

Inventor： VISWANATH PRAMOD ,  RANGAN SUNDEEP ,  LI JUNYI ,  LAROIA RAJIV

IPC: H04B1/713 ,  H04B1/7143 ,  H04B1/7156 ,  H04B7/26 ,  H04J11/00 ,  H04L5/02 ,  H04L27/26 ,  H04Q7/36 ,  H04B1/76

Abstract: A base station having the strongest downlink signal is identified by utilizi ng a unique slope of a pilot tone hopping sequence being transmitted by a base station. Specifically, base station identification is realized by determining the slo pe of the strongest received pilot signal, i.e., the received pilot signal having the maximum energy. In an embodiment of the invention, the pilot tone hopping sequence i s based on a Latin Squares sequence. With a Latin Squares based pilot tone hopping sequence, all a mobile user unit needs is to locate the frequency of the pilot tones at on e time because the pilot tone locations at subsequent times can be determined from the slop e of the Latin Squares pilot tone hopping sequence. The slope and initial frequency shift of the pilot tone hopping sequence with the strongest received power is determined by employing a unique maximum energy detector. In one embodiment, the slope and initial frequency shift of the pilot signal having the strongest received power is determined by finding the slope and initial frequency shift of a predicted s et of pilot tone locations having the maximum received energy. In another embodiment, th e frequency shift of the pilot signal with the strongest, i.e., maximum, received power is estimated at each of times "t". These frequency shifts are employed in accordance with a prescribed relationship to determine the unknown slope and the initial frequency shift of the pilot signal.

公开(公告)号：BR0100361A

公开(公告)日：2001-10-02

申请号：BR0100361

申请日：2001-02-05

Applicant: LUCENT TECHNOLOGIES INC

Inventor： LAROIA RAJIV ,  RANGAN SUNDEEP ,  UPPALA SATHYADEV VENKATA ,  LI JUNYI

IPC: H04J11/00 ,  H04B7/26 ,  H04L5/02 ,  H04L7/00 ,  H04L27/26

Abstract: An uplink synchronization and access control system is provided, in which mobile stations transmit certain timing and access signals in dedicated intervals in an uplink stream. Access control is illustratively implemented as a two-stage process, in which a given mobile first transmits a generic uplink access signal, in one of the intervals. If this access is accepted, the base station transmits an access acknowledgment, which contains initial timing and power corrections, along with initial channel assignments, on which the mobile can initiate a call set-up process. For re-synchronization, mobiles transmit timing synchronization signals in the dedicated timing and access intervals. The base station measures the arrival time of the signals, and sends back appropriate timing corrections. The invention thereby ensures that orthogonality between mobiles is maintained.

公开(公告)号：BR0100359A

公开(公告)日：2001-10-02

申请号：BR0100359

申请日：2001-02-05

Applicant: LUCENT TECHNOLOGIES INC

Inventor： LAROIA RAJIV ,  RANGAN SUNDEEP ,  UPPALA SATHYADEV VENKATA ,  LI JUNYI

IPC: H04J11/00 ,  H04B7/26 ,  H04J3/06 ,  H04L5/02 ,  H04L7/10 ,  H04L27/26 ,  H04Q7/30

Abstract: Timing and access signals, to be transmitted in designated timing and access intervals, are constructed from orthogonal multitone signals. The multitone signals may be similar to multitone signals used in OFDM data transmission, except that a cyclic prefix, which is associated with reception of the signals in a base station, is extended to cover the timing errors of mobile stations not yet synchronized. Design techniques which optimize the time resolvability and peak-to-average ratio of the multitone signals, an efficient fast Fourier transform (FFT) based technique for maximum likelihood timing estimation, and a robust linear filtering technique for averaging timing estimates from different synchronizations, are also provided.

公开(公告)号：BR0006806A

公开(公告)日：2001-07-24

申请号：BR0006806

申请日：2000-12-15

Applicant: LUCENT TECHNOLOGIES INC

Inventor： LAROIA RAJIV ,  LI JUNYI ,  RANGAN SUNDEEP ,  UPPALA SATHYADEV VENKATA

IPC: H04J11/00 ,  H04B1/7136 ,  H04B1/7143 ,  H04L5/02 ,  H04Q7/22

Abstract: Tone sequences in a frequency hopping arrangement are generated and assigned by advantageously employing a combination of a sequence generator and a sequence assignor to generate sequences and assign them on a time slot by time slot basis. In a transmitter, the sequence generator and sequence assignor, in combination with a user tone assignor are employed to generate and assign tone sequences to a user on a time slot by time slot basis. In a receiver, the sequence generator and sequence assignor, in combination with a user tone identifier are employed to generate sequences and to identify incoming tone sequences to a user on a time slot by time slot basis. Specifically, the sequence assignment in a time slot is such that a prescribed plurality of sequences is assigned to a particular user. This partitioning of the tasks facilitates the use of a sequence generator that generates sequences with the desirable properties of interference and frequency diversity and, which, leaves the task of properly assigning these sequences among one or more users to the sequence assignor. The sequence assignor functions in such a manner that the interference and frequency diversity properties for the one or more users are preserved, and this is further facilitated by assigning sequences in such a manner that they maximally overlap prior assigned sequences. In one example of the invention, a Latin square based sequence is generated in accordance with a first prescribed process. In an embodiment of the invention, a Latin cube based sequence is generated in accordance with a second prescribed process. In another embodiment of the invention, a Latin hypercube of prescribed dimension based sequence is generated in accordance with a third prescribed process. In still another embodiment of the invention, the principles of the invention are employed to realize frequency band hopping.